Agricultural seed planting is typically accomplished by multi-row planters. Each planter row unit is adapted for opening a seed trench, depositing seeds within the seed trench, and closing the seed trench around the seeds. Additionally, many other attachments, such as chemical applicators, may be added to the row units.
The row units typically utilize closing wheels positioned at the trailing end of each row unit for closing the seed trench. These closing wheels squeeze soil from each side of the trench around the seed to close the seed trench. A spring loaded down pressure applied to the closing wheels may be variably adjusted to account for different soil conditions.
Closing the seed trench by compressing the sides of the trench frequently results in poor seed to soil contact which enables air pockets to remain in the seedbed. Such air pockets allow the plant to leaf out underground, thereby inhibiting emergence of the plant from the seedbed. Additionally, in dry conditions, it is not uncommon for the closed seed trench to crack open and expose the seeds contained therein. In either case, poor seed to soil contact may result in large numbers of lost plants.
Furthermore, when planting in heavy or moist soils, it is typically necessary to maximize the down pressure applied to the closing wheels to completely close the seed trench. The increased down pressure tends to compact the soil above the seed, thereby inhibiting the emergence of the plant. In moist or gumbo soils, the compacted soil above the germinating seed may dry out and form a hard crust layer which would further inhibit plant emergence. Should the closing wheels encounter light or sandy soils while set at maximum down pressure, the seeds at the bottom of the trench may be forced up into dryer soil adjacent the top of the seedbed. When the seed is positioned near the top of a dry seedbed, the seed is more likely to be lost to wind erosion. Even if the seed remains within the seedbed, it may germinate improperly due to a lack of moist soil.
The problems of soil compaction in heavy or moist soils, and poor seed to soil contact in all soil types, are inherent with agricultural planters which use closing wheels to compress the seed trench. These problems are magnified when different soil types are combined within a single field. Therefore, row unit attachments that may alleviate one type of problem in one type of soil may be ineffective against other types of problems or in other types of soil. For example, row leveler chains pulled behind the closing wheels may reduce the tendency of some soils to crust. However, leveler chains will not enhance seed to soil contact and are not typically used in moist soils or in combination with chemical applicators. Thus, the prior art does not teach any single solution to these problems that would be effective across the entire range of soil types and that would be compatible with all commonly used row unit attachments.
It is with regard to this background information that the improvements available from the present invention have evolved.